Household carbon caps and tariffs: A living lab experiment

Abstract

Transnational efforts to combat climate change are intensifying, with Germany targeting net-zero emissions by 2045. The residential sector is a significant CO₂ emitter but lacks direct mitigation strategies, such as personal carbon budgeting and trading, which are common in industry. Although theoretical research on personal carbon trading exists, real-world household-level studies are scarce. This study addresses that gap by examining the implementation of household carbon caps and tariffs in a living lab experiment. Conducted in the Energy Smart Home Lab, the experiment involved three households under weekly carbon caps, with the option to purchase additional allowances under two different tariffs. In two households, photovoltaic feed-in was accounted for to incentivize load shifting and maximize self-consumption. Additionally, participants were encouraged through economic and non-economic incentives to adhere to a 2 kW power limit during simulated grid congestion. Real-time energy consumption monitoring and weekly interviews provided insights into how participants responded to the imposed carbon limits and power restrictions. Essential household activities, such as cooking and heating, occasionally took precedence over economic motivations, leading to breaches of the power limit. As weekly carbon emission caps were reduced by 45 % to 75 % by the end of the intervention, participants faced substantial challenges, compounded by unmodifiable appliance emissions and external pressures like exams. Although limited in sample size, this study is the first to combine carbon caps, tariffs, real-time feedback, and photovoltaic-based incentives in a living lab setting.